Electrical connecter plug



Nov. 5, 1935. fc. E. GILBERT 2,019,532

ELBGTRICAL CONNECTER PLUG Filed Sept. 16, 1933 -Patented Nov. 5, 1935 y f 152,019,53-zy UNITED STATES PATIEIN'I"l OFFICE f 2,019,532 r ELECTRICAL CONNECTER. PLUG Charles E. Gubert. New York, N. Y. 4spplicamm september-1s, 193s; serial No. 689,711 y* This invention relates to devices for making electrical connection between an outlet for electrical current and an appliance or between two electric cords. and numerous other uses which will be evident to those skilled in the art.

Unlike the plugs which are in common use today this plug may be attached to the electric cord or other circuit without the removal of the insulation from the wires of the cord, and withdescription is an electric plug of generally conventional form since it is perhaps the\simp1est -and easiest to describe, it will be understood that its external form is immaterial and that it need not even be a. separate unit but may form an lntegral part of another electrical device such, for example, as a socket or vacuum cleaner.

A plug made in. accordance with the invention is illustrated in the accompanying drawing, in which Figure 1 is a side elevation oi an assembled plug with an electric cord attached;

Fig. 2 isan end elevation-of the plug'of Fig. 1; is another side elevation of the same plug rotated 90 from the position-shown in Fig. 1 to illustrate the depressed linger grips by means oi' which it may be readily removed from the" electrical outlet or appliance;

Flg..4 is an end elevation of the body of the plug showing the recesses in which the contact blades are seated 'and otherdetails, one recess containing a contact blade, the other being empty;

Fig. 5 is a cross-section oi' the plug along the line 5 5 of Fig. 2 showing one of the recesses with a contact blade in position thereinand in contact with one of the insulated wires of .an electric cord;

ng. e is a cross-section of a plug alongl the uneD 8--5 of Fig. 4;

Fig. 7 is also across-section along the line 1-1 of Fig. "4 illustrating particularly the position assumed by the wires of the' electric cord;

Fig. 8 is a fragmentary cross-section along the 9 Claims. (Cl. 173,-361) line 8-8 of Fig. 4 to illustrate the preferred 'shape of the diagonal channel for the wires between the central opening of the -plug and the recesses and Fig. 9 is an enlarged fragmentary diagrammatic view along the line 9-'9 of Fig. 4. As will be seen from the drawing the plug consistsof but four parts,-a body l of substantially conventional external` shape which may be molded from bakelite or suitable finsulating matej rial in a single ,piece and by a.y single molding 10 operation, two contact blad 2, each .of which may be stamped from a single piece of metal and also shaped by a single operation, and a disc 4 or insulating material which may also be formed by f a single stamping operation and which closes the open end of the body. A

Theexterior of the bpgly may be provided with depressed finger grips 5 toy make it possible to remove it easily fromthe outletfor appliance.

The body is provided with the usual longitudinal` '20 central aperture .6' through which the electric cord is inserted and also with two recesses l in which the contact blades. are positioned. A channel 9 runs diagonally across the open face of the plug from substantiallyA one corner-'of -one 85 recess to substantiallythe other corner o! the other `recess intersecting the `central aperture. Through this channel the respective electric wires of the cord are led to the contact elements seated in the recesses. Preferably that ypart of the Si)I channel l0 between each recess and the central aperture 6 narrows from the upper edge towards the bottom as shown in Figs. 4 and 8, its dimensions in 4this portion being suchA that the electric wire lying therein will be wedged so/that it will.

assume any strain placed upon the cord and will not permitsuch a strain to be conducted to the pointsof contact between the wire and the 'con' tact blades. The ends ofchannel 9, asshown at Il in Fig. 4, are not so narrowed, extend to the 40 bottom of recess 1 and the bottoms preferably curve. upwardly and'outwardly as best shown in Fig. 7 to accommodate the free end` of each.

electric wire.

The open end of the body is depressed somewhat as best shown at l2 in Fig. 6 to provide a peripheral shoulder I3 around this end oi' theplug, this shoulder being formed so as to have a slightly undercut internalface Il.

The contact blade receiving recesses 'I are gen- 50 erally rectangularin shape, the inner wall being parallel to the' central longitudinal axis of the plug, and thevouter wall being-generally parallel to the inner wall butprovided with an Vinwardly projecting shoulder I6 at .its lower 'end which 55 causes a constriction of the extreme lower'part of the recess into which the end of the contact element will snugly fit. Near the upper edge of f the outer wall on both sides of its mid-portion are inwardly projecting shoulders I1 which, as will be later described, engage with a part of the contact blade to retain the blade rigidly in position and prevent accidental displacement. Between shoulders I1 a depression 28 in the outer wall of recess 1 may be provided into which portion 24 of the contact blade may recede after the blade is inserted into the recess. At the end of each recess 1 where it is intersected by channel 9 shoulder I6 is terminated as shown in Fig. 4 leaving channel 9 free and clear with ample room for the insulated wire adjacent the point 'at which the blade makes contact with it. n

The disc 4 which closes the body after the contact .blades andwires have been assembled is shown at 4 in Fig's. 2, 5-and '1. It is generally similar to the disc employed with plugs of common construction in that it fits the open end of the b ody and is provided with two apertures through which the contact blades pass. But'unlike the ordinary disc instead of being retained simply by friction with the contact blades it snaps under under-cut edge I4 of the body and is thus iirrnly held in position, considerable effort being required todisplace it. The shape of this' disc which is shown with two curved cutaway portions is not material. It merely lends itself more I perfectly to the body having the depressed nger grips. If'these are omitted or if otherwise desired the disc may be of ordinary circular shape.

'Ihe contact blades 2 and 3 are best illustrated in Figs. 5, 6 and 9. Each may be formed from a flat piece of resilient conducting material by asingle stamping and bending operation. Eachy consists of a prong I9, the form shown being that ,suitable for use with present day electrical outlets, a base portion 20 which seats in the recess of the body, an insulation piercing and-contact making portion 2|, and a portion 21 which engages with the shoulders I1 ofthe recess to lock the contact blade therein. Base portion 26 is simply an enlarged extension` of prong I9 the width of which is such as to fit snugly but re-v i '.movably in the recess. `At one lower corner, base portion 20 is cutaway slightly and its lower edge -provided with a series of teeth 22.y The inner edge of this cutaway portion is also slit upwardly-al short distance as shown at 23, which permits bending inwardly the edge which carries the teeth as 4best shown in Fig. '1. Toothed portion 22 when the contact blade is seated in the recess lies in the enlarged portion of the recess formed by the intersection therewith of diagonal channel 9, the teeth 22 lying close to but spaced slightly apart from the inner wall of the recess with teeth22 facing theinner wall. Portion 24'of the contact ,blade is formed by longitudinally slitting the blade as shown at 25 and also slitting base 20 to forman arrow-shaped head 26. This tongue is bent as shownin Figs. 6 and 9 so that its point lies substantially in the plane of the base 20 but the upper edges 21 of the arrowhead project outwardly from that plane. These edges 21 are so positioned that when the contact blade is inserted in the recess they will klie just lbelow the lower edge of shoulders I1, the intermediate part passing between shoulders I1 into recess 28.

The plug is Vassembled as follows: A length of 'cord is passed through the central opening 6 and the outer woven insulation stripped from its end the wire down into it. As soon as appreciable pres- 5 sure has thus been placed upon the wire the part lying in the restricted portion I0 of channel 9 will become wedged and immovable therein. Consequently further downward motion of the contact blade into recess 1 will cause teeth 22 toscrape along 10 the insulation of the wire until the contact blade is fully seated a'nd to strip the insulation from the wire to that extent. This will also cause the teeth to scrape and enter between the strands of the wire itself to some extent making a clean and eflicient 15 contact therewith. This portion of the wire being jammed between the inner wall of the recess and the inwardly extending toothI portion of the contact, this action i's positive and cannot fail to occur. During this operation the spear-headed 20 tongue 26 has also entered the recess, this being made easy by the fact that its point lies inf' the same plane as the rest of the base 20, and outwardly projecting shoulders 21 have passed under shoulders I1 and now rest directly below and 25 bearing against the shoulders. This effectively locks the contact blade into the recess. It cannot be removed unless shoulders 21 of the contact blade are sprung back out of contact with shoulders I1 of the recess. This cannot be done 30 without the use of some sort of a tool. Therefore the contact blades are secure againstaccidental displacement. Disc 4 may then b'e slipped over prongs 2 and 3 and snapped into position under shoulder I3 closing the open end of the body. 35 This disc is not essential since it is not intended to assist in the supporting orv retaining of the contact blade and, since there is no exposed conductor, there is rno possibility of short-circuiting as in the ordinary type of plug. Therefore, if de- 40 sired, this disc may be eliminated. In that `case throughout.

lThus by simply bringing the cord into the 45' plug, laying the wires'across the recesses ln the channel provided therefor, andinserting the contact blades in the recesses the entire plug is assembled, a perfect and enduring electrical contact, is made with the conductors through the 50 insulation thereof withoutexposing the conductors at any point where a short-circuit might occur and the entire assembly is maintained in. this"assembled condition without'the aid of any screws, rivets, or other similar bolting means. 5 5

At the same time the plug may be disassembled simply by disengaging the contact blades from the shoulders of the recesses and pulling them, out. That part-of the cond ctor at which electrical contact is made Ais pr tected from all ex- 60' ternal strain by the fact that the part lying in the constricted channel I0 is wedged tightly therein and will 'absorb it. The greater the strain the tighterl this part of the conductor will be held. Thus the necessity of tying the two 66 conductors together to obtain a knot larger than the central opening for thepurpose of absorbing external strains is, eliminated.

What I claim is: A 1. An electrical connecter which consists of 70 a body providedl` with a longitudinal recess a wallof which has a shoulder adjacent its outer end, a contact blade seated in said recess and provided with means to pierce the insulation of an insulated wire and to make contact with the 15' position with 2. An electrical connecter comprising a body f conductor within the insulation, and also provided with a resilient tongue having a shoulder which engages under the shoulder of said recess wall to lool; the blade within the recess against retraction to maintain it positively in contacting the conductor.

having a longitudinal recess a wall of which is provided with a shoulder adjacent its outer end and a. central longitudinal aperture, a transverse channel intersecting said aperture and also said recess adjacent one end, a contact blade having a stepped edge seated in said recess, that portion of the stepped edge the intersecting channel having means for piercing the insulation of an insulated wire and mal-r-v ing contact with the wire within, said contact blade also having means cooperating with said shoulder to lool:` said blade within said recess against retraction and to maintain it positively in Contact with the wire.

. 3. An electrical connecter comprising a body having a central longitudinal aperture and a longitudinal recess for the reception of -an insulated wire and a contact blade, one side wall of which is substantially parallel tothe longitudiriai axis .of the body, a contact element seated within said recess and having on one part of its lower edge means for `jamming an insulated wire against said wall of said recess, said last mentioned means also being adapted to pierce and to strip the insulation from that part of an insulated wire which is jammed against said wall, said contact blade also being provided with means which cooperates with means in said recess to lock it within said recess against retraction and in wire contacting position.

4. An' electrical connecter comprising a body having a central longitudinal aperture vand a longitudinal recess a wall of which is provided with a shoulder for the reception of an insulated wire anda contact blade, one side wall oi which is substantially parallel to the longitudinal axis of the body, a contact `blade seated within said recess and having on one part of its lower edge means for jamming an insulatedwire against said wall of said recess, said last mentioned y means also being adapted to pierce and to strip the\insulation from that part of an insulated wire which is jammed against said wall, said contact blade also being provided with integral means for locking it within said recess in wire .contacting position, said locking means consistingof a resilient tongue one end of which is offset to engage with the shoulder on the recess wall.

5. An electrical connecter comprising afbody having a' longitudinal recess, a shoulder projecting into said recess adjacent its open end, a central longitudinal aperture separated which registers with `the contact blade is from said recess by a wall, a tverse :im in. tersecting Saidentral aperture walland recess along which an' insulatedwire may be conducted from said central aperture into said recess, that portion of said channel which `intersects said wall being narrowerk towards its bottom and shallower than the other portion, a contact blade seated in said recess and provided with means for jamming an insulated wire against said wall, and for` stripping the insulation from that of the insulated wire which is jammed` against Part l@ the wall, making` contact with the conductor within, and means on said blade engaging under said shoulder in said recess to lock said blade within said recess.

l5 6. An electriccormecter comprising a body provided with a longitudinal recess, a contact blade seated within said recess having an odset upwardly extending resilient tongue, a, shoulderA I on a wall of said recess the under side ot which 2 engages with saidtongue to lock said contact blade, Within said recess against retraction, and means on that part of said contact blade .which is seated in the recess for piercing the insula- With the wire within.

7. An electric connecter comprising a body having arecess for the reception of an insulated wire, a contact blade one end of which is seated within said recess, said end terminatingin means 30 for piercing the insulation of an insulated wire and making contact with the wire within, an oiset tongue on said blade, a shoulder in said recess engaging with said, tongue to lock said blade within said recess wire contacting position.

8. An electrical connecter comprising a body provided with a longitudinal recess for the reception of a contact blade, a, .contact blade adapted Yto be seated in said recess means forp'iercingthe insulation of an insulated wire and for making contact with the wire within when said blade is seated, a locking member on said blade which engages with the body when fully inserted into itsrecess to positively lock it against retraction and in wire contacting position. v y 9. An electrical connecter comprising a body provided with a longitudinal recess for the reception of a -contact blade, to be seated in said recess and provided with means for piercing the insulation of an insulated wire and for making contact with the wire with. in when-said blade is seated, a locking member on said blade which engages with a` wall of said 5 CHARLES E. GILBERT,4

.tion of an` insulated wire and making contact '25 against retraction in 35 and provided with o a contact blade adaptedy 

